Material handling slings



y 8, 1957 J. B. MALLARD 2,793,903

MATERIAL HANDLING SLINGS Filed Jan. 23, 1953 2 Sheets-Sheet l (James B.Ma Hard INVENTOR.

BY Q g a A TTORNE Y y 8, 1957 J. B. MALLARD 2,793,903

MATERIAL LHANDLING SLINGS Filed Jan. 23, 1953 2 Sheets-Sheet 2 dam es 5.Mafia/'0 INVENTOR.

B QM 6 #w r 2,193,903 Ice Patented May 28, 1957 MATERIAL HANDLINGSLINGS' James B. Mallard, Houston, Tex.

Application January 23, 1953, Serial No. 332,899

4 Claims. (Cl. 294-74) This invention relates to an improved sling forhandling material, and particularly to a sling for handling covered orcoated pipe.

Each year more and more material which is conveyed from one location orposition to another by material'handling equipment is provided with aprotective coating or covering. For example, the large pipe used inconveying petroleum products, such as natural gas, is generally covered,as with fibre glass, paper and tar, to reduce the deterioration effectsof moisture and of the soil in which it will be buried. Consequently,the sling used in handling this pipe should be so designed that it willnot tear this protective covering. Standard wire rope slings are notsuitable for this purpose both because of the rough surface of the ropesthemselves, because of the dangerous and awkward irons, or end members,used, and because of the distribution of the load on such a smallsupporting area. With such slings the covering often is damaged duringhandling and frequently tears when the sling is withdrawn, after thepipe is laid in the ground. Moreover, smooth surface belt type slingssuch as those made of duck and rubber, or nylon and rayon, have not,when used alone, been satisfactory for this purpose. One reason is thatthe belts stretch every time the load is put on them and this stretchingis frequently sufficient to tear the pipe covering. Moreover, suchbelts, particularly after long usage, will be strained to the point ofbreaking without the weakness being noticeable to the eye. Consequently,they are subject to sudden complete failures, sometimes with disastrousresults to men, material I A compromise sling is sometimes used whichcomprises a standard wire rope sling having its and equipment.

ing or tearing of the covering or coating upon withdrawal of the slingfrom under the pipe, after it has been laid in position. While suchcomprise slings are an improve ment over the standard slings justdescribed, the entire load is still carried on the relatively small areapresented by the cables themselves. This unequal load distribution oftencauses damage to the pipe covering at the point where the cables contactit through the sling belt. Moreover, the means of connecting the cablesto their respective end pieces, and the cables themselves, except alongthe intermediate portions of their lengths, are not covered by the belt.Consequently, there is still some danger of tearing the pipe coveringwhile withdrawing the sling. In addition these belts have not beensatisfactorily anchored in place, relative to the wire ropes.Accordingly it is the primary object of this invention to provide a newand improved material handling sling in which the load of the materialhandled is properly distributed over a relatively large bearing area.

Another object of my invention is to provide a new and improved slinghaving a contact face smooth enough for safe handling of coated orcovered material without damage thereto.

It is a further object of my invention to provide a sling so designedthat it can be withdrawn from under the load without likelihood ofdamage to the load surface.

It is a still further object of my invention to provide an improvedsling which is strongand durable, relatively inelastic, and which is notlikely to fail without giving clear and early warning.

Other objects as well as advantages of myinvention will be pointed outin the following specification and appended claims. I

' In the presently preferred embodiment of my invention I provide amaterial handling sling having both the advantages of the standard wirerope sling and the belt type sling, along with new and improved featuresnot present in either type. I provide a plurality of wire ropes, usuallyfour, which are permanently joined together at their respective ends toform, in effect, an endless rope arrangement. At each end of the sling,where the ends of the ropes are joined together, the arrangement adaptsitself for ready attachment of both ends to a single grappling hook orthe like. This eliminates the customary irons, or end members, which aredangerous to personnel and difficult to use without damage to theprotective covering of the load. The wire ropes are spaced apartthroughout a major portion of their lengths by spreader bars placed nearthe respective ends of the sling. Along the load supporting portion ofeach wire rope, between the spreader bars, are attached a plurality ofbearing plates, the surfaces of which may be suitably curved to conformto the contour of the material handled. The bearing surface of theseplates, the load portion of the wire ropes, and, preferably, thespreader bars, are shielded from contact with the material handled bymeans of a protective covering. This covering is usually in the form ofa belt which may vary from a friction surface conveyor belt to a softrubber, according to the nature of the expected load. For best resultsthis cover or belt is attached to at least some, and preferably all, ofthe bearing plates by means of suitable bolts. The bolt heads, whilepreferably on the load contacting side of the belt, are drawn into arecess in the face of the bearing plate below its contact surfaces, upontightening of-the attaching bolts.

While not essential to the operation and successful use of my sling, Iprefer to extend the covering belt not only to cover the spreader meansat each end of the sling, but at one end to cover a substantial portionof the wire ropes extending beyond the spreader bar. This gives addedprotection to the surface of the material handled, particularly in thecase of a coated or covered pipe. When the sling is withdrawn after thepipe is in position in the ground, the belt cuts a channel in the softearth below the pipe through which the uncovered end portions of theWire ropes can be withdrawn without cutting or tearing the pipe coating-Moreover, when the belt extends substantially to the end of the wireropes at one end of the sling, as in my preferred embodiment, it givesadded assurance that the pipe covering or coating will not be damaged bycontact with the wire ropes. In handling pipe for burial in the groundthe sling is withdrawn by unhooking the end having the additional beltcovering and exerting a pulling force on its other end.

My invention will be more fully understood from the following detaileddescription taken in connection with the accompanying drawings and itsscope will be pointed out in the appended claims.

In the drawings Fig. 1 is a top plan view, fragmentary in its centerportion, of the sling, showing the contact surface of the belt; Fig. 2is a bottom plan-view, fragmentary in its center portion, illustratingthe positioning of the spreader bars and bearing plates; Fig. 3 is asectional view of a spreader bar, taken along the lines 3-3 of Fig. 2;Fig. 4 is a sectional view of a bearing plate, taken along the lines 44of Fig. 2; Fig. is a sectional view of the bearing plate of Fig. 4 takenalong the lines 5- 5; and Fig. 6 is a sectional view similar to Fig. 5but showing a modified clamping cleat for use with the bearing plate.

Referring now to Figs. 1 and '2 of the drawings, a sling 1 is providedwith a plurality of substantially inelastic strength members 2 which arepreferably wire ropes. The ropes -2 are permanently joined together at"their respective ends to provide end members 3 and 4 by which the slingcan be attached to a single lift member, not shown, such as a grapplinghook. The Wire ropes or cables 2 are preferably so joined as to providea smooth end which can be withdrawn from underneath the material handledwithout likelihood of damaging it.

In order to space the wire ropes, which in the form shown may beconsidered portions of a continuous wire rope, I provide spreading meansin the form of bars 5 'and 6 attached to the respective cables by cleats7 and "suitable bolts '8. Between the spreader bars, which are fixed tothe cables near their respective ends, the wire ropes form a flexiblesupporting frame of sufficient length to cradle the particular materialor pipe size to 'be handled. The relative inelasticity of the wire ropesforming the sling cradle limits the stretching of the sling contactsurface, and the fact that a plurality of ropes are used, which arereadily visible from below the sling provides insurance against suddenfailure of the sling while under load conditions. Moreover, any desiredstrength can be obtained merely by changing the size of the wire ropeused.

The spaced wire ropes distribute the load in a manner suitable for manymaterial handling operations. In the case of the handling of material inwhich special care is required, however, such as covered or coated pipes(which are considered as equivalent in the description of thisinvention, and in the appended claims) an even better load distributionis desirable. Accordingly I attach a plurality of bearing plates 9 toeach of the wire ropes 2 at spaced intervals extending over a greaterpart of the distance between the spreader bars 5. These bearing plates 9are preferably curved in the manner shown in Fig. 4, to conform to thecontour of the material to be handled, such as the circumference of apipe. As best shown in Figs. 2 and 5, each bearing plate 9 is securelyattached to its wire rope by means of a cleat or strap 10 and a pair ofbolts 11, one on each side of the wire rope and each extending throughthe bearing plate. Suitable nuts 12 are used for tightening the strap 10against the rope and plate. The bearing plates may be of any suitablematerial such as cast aluminum, and in like manner the clamping cleatsor straps 19 may be of a similar material, it being preferable that theybe of a relatively soft material compared to that of the wire ropes, sothat, upon tightening the nuts 12, the straps It) may bend slightly toaccommodate the cable. I have also found it preferable to form thebearing plates with a longitudinally extending notch or recess 13 toaccom- -modate the cable. By making this recess in the general form of aV, I find that upon applying pressure by means of the clamping cleat 10,the cable 2 is wedged securely, thereby preventing relative movementbetween it and the bearing plate. In :the embodiment shown in thedrawings the bearing plate is made thicker in the center portion fromend to end in both a longitudinal and lateral direction. This is both toaccommodate the longitudinal recess 13 and to provide additionalstrength to the bearing plate.

Referring again to Fig. 1, I provide a protective con- 'tact surface formy sling by means of a beltor other 'covering-14,' =which belt may bemade of any suitable material such as 'duck'and' rub-her, soft rubber,or other material, depending on the nature of the load which is expectedto be handled. In the case of handling coated pipe I prefer to use duckand rubber belting with a friction surface. This belt covers the contactportion of the sling completely, extending from the spreader bar 5 tothe spreader bar 6, and, in the preferred form shown, extending beyondthe spreader bar 5 substantially to the end of the sling to protect thepipe upon withdrawal of the sling by pulling on the other end. Theextended portion of the belt 14 preferably tapers toward the end of thesling, and may be secured to the wire ropes beyond the spreader bar bymeans of a strap 15 positioned beneath the ropes, into which extendscrews or bolts 16. The heads of the bolts 16 are on the contact side ofthe belt but are withdrawn below the contact surface upon beingtightened, thereby preventing contact with the pipe upon withdrawal ofthe sling.

It will be understood, of course, that the belt 14 does not in itselfsupport the weight of the load, and therefore is not subjected to theusual stresses which tend to stretch and strain similar belts inconventional slings. Instead the strength members 2 carry the weight,which is distributed over a relatively large area by means of thebearing plates 9 fixed thereto.

To secure the belt 14 in proper position I attach it to the cables 2 bysecuring it to the bearing plates 9.

One suitable means of attaching the belt to the bearing plates is toinsert the bolts 11, used to tighten the clamping cleats 14 through thebelt so that the bolt heads 17 are located on the contact side of thebelt. This guards against relative movement between the cables, thehearing plates, and the belt in a simple, economical and reliablefashion. As best seen in Figs. 4 and 5, the heads 17 of the bolts 11,which are preferably elevator type bolts, are drawn below the contactsunface of the belt into a recess 18 in the central portion of thecontact face of each bearing plate 9. The tightening of the nuts 12,therefore, not only brings the clamping cleat '10 securely into positionto wedge the wire rope 2 into the groove 13, but draws the bolt heads 17tightly into the recess 18 to prevent their contact with the materialhandled by the sling.

While it is not essential that the bearing plates 9 have their bearingsurfaces curved to the exact contour of the material handled, it isdesirable, particularly when the sling is designed for use in handlingpipe, that such plates be curved to correspond in a general way with thecurvature of the outer surface of the pipe. Plates of a fixed curvaturecan be used for handling pipes of varying sizes within a general range,however, and it will be understood that even plates with fiat surfacescan be used in handling some material.

In Fig. 6 l have shown a modification of the clamping cleat which issometimes useful when the diameter of the wire ropes on which thebearing plates will be attached is not determined before-hand. Theclamping cleat 10a I shown in Fig. 6 has a projection 19 dependingtherefrom which will bite into the cable 2 to insure against relativemovement between the cable and the bearing plate 9 even in the event thecable is of such small diameter that, when laid into the bearing plategroove, it does not protrude above the back of the plate. Such cleatscan be used even when larger cable is employed, as the material used inthe cleat is soft reiative to that used in the wire rope; consequently,the projection, while increasing the contact pressure between the cloatand the rope, will not damage the rope to any substantial degree.

While the present invention has been described by reference to theparticular preferred embodiment shown in the drawings, it Will beunderstood that this is by Way of illustration of the principlesinvolved and that those skilled in the art may make many modifications.Therefore, I contemplate by the'appended claims to cover any suchmodifications as fall within the true spirit and scope of thisinvention.

What I claim is new and desire to secure by Letters Patent of the UnitedStates is:

1. A load supporting sling comprising a plurality of substantiallyparallel lengths of wire rope, each of said lengths having attachedthereto a plurality of bearing plates, each of said bearing plateshaving a load-supporting surface of substantial area and being attachedto a single one of said lengths, and a flexible sheet attached to theload-supporting surface of each of several bearing plates to cover saidbearing plates and said lengths to shield the load to be carried fromcontact therewith.

2. A wire rope sling for handling covered pipe comprising a plurality ofsubstantially parallel lengths of flexible wire rope serving as strengthmembers, said lengths being joined together at their adjacent ends toform loops at opposite ends of said sling adapted for simultaneousengagement by a single lift member, a spreader bar adjacent each of saidloops extending transversely across and secured to each of said lengthsto separate and to space said lengths, a plurality of bearing platessecured along each said lengths, each of said bearing plates having aloadsupporting surface curved substantially to the contour of the pipeto be handle, and a flexible sheet attached to and covering theload-supporting surfaces of said bearing plates, said sheet extendingover both of said spreader bars and over the length of wire ropetherebetween.

3. A sling for handling coated or covered pipe comprising a plurality offlexible wire ropes serving as substantially inelastic strength members,said ropes being joined together at their adjacent ends to form loops atsaid ends adapted for attachment to a single lift member, spreader meansnear each of said loops for spacing said ropes apart along the majorportion of their lengths, and a sheet member attached to the loadcarrying sides of said ropes to cover both of said spreader means andall of the ropes itherebetween, said sheet member extendingsubstantially to at least one extremity of said sling.

4. A material handling device comprising a plurality of elongateflexible and substantially inelastic strength members, said strengthmembers being joined together at their adjacent ends to form loops, aspacer bar near each of said loops for spacing apart said strengthmembers throughout the load carrying portion of their respectivelengths, a plurality of separate bearing plates attached to each of saidstrength members, and a flexible sheet 31ttached jointly to at leastsome of said bearing plates to cover both of said spacer bars, thestrength members therebetween and all of said bearing plates.

References Cited in the file of this patent UNITED STATES PATENTS1,168,802 Harrison Jan. 18, 1916 1,207,795 Riekenberg Dec. 12, 19162,598,921 Knudsen June 3, 1952

